#define _CRT_SECURE_NO_WARNINGS 1

#define SWAP_BIT(n)      (n = ((n&0x55555555)<<1) + ((n&0xaaaaaaaa)>>1))

int main()
{
	int a = 11;
	SWAP_BIT(a);
	printf("%d\n", a);

	SWAP_BIT(a);
	printf("%d\n", a);
	return 0;
}